1303 Bacterial DNA induces regulatory B cells and attenuates lupus through a B cell-extrinsic, TLR9-dependent mechanism

[IL-21 induces regulatory B cell differentiation and immunosuppressive effect through cognate interaction with T cells].

For a long time, it has been thinking that B cells regulate immune responses by producing antigen-specific antibodies. However, previous studies have revealed that specific B-cell subsets can also negatively regulate T-cell immune responses, and have been termed regulatory B cells. Recently, our study showed that mouse CD1d(hi)CD5(+) B cell subsets mainly produce IL-10. Therefore, we named thes...

A TLR9-dependent checkpoint governs B cell responses to DNA-containing antigens.

Mature B cell pools retain a substantial proportion of polyreactive and self-reactive clonotypes, suggesting that activation checkpoints exist to reduce the initiation of autoreactive B cell responses. Here, we have described a relationship among the B cell receptor (BCR), TLR9, and cytokine signals that regulate B cell responses to DNA-containing antigens. In both mouse and human B cells, BCR ...

CpG inhibits pro-B cell expansion through a cathepsin B-dependent mechanism.

TLR9 is expressed in cells of the innate immune system, as well as in B lymphocytes and their progenitors. We investigated the effect of the TLR9 ligand CpG DNA on the proliferation of pro-B cells. CpG DNA inhibits the proliferation of pro-B, but not pre-B, cells by inducing caspase-independent cell death through a pathway that requires the expression of cathepsin B. This pathway is operative i...

TLR2-Dependent Activation of b-Catenin Pathway in Dendritic Cells Induces Regulatory Responses and Attenuates Autoimmune Inflammation

TLR7/TLR9- and B Cell Receptor-Signaling Crosstalk: Promotion of Potentially Dangerous B Cells

B cells are capable of receptor-mediated responses to foreign antigens. Recognition of microbial-derived nucleic acid (NA) by toll-like receptors (TLRs) 7 and 9 in B cells has been substantiated. Endogenous NA released from damaged or dying cells can also be immunogenic in certain contexts and can incite aberrant activation of B cells. When TLR-driven B cell receptor (BCR)-activated B cells are...